﻿using System;
using System.Collections.Generic;
using System.Reflection;
using MongoDB.Bson;
using MongoDB.Bson.IO;
using MongoDB.Bson.Serialization;
using MongoDB.Bson.Serialization.Serializers;

public class StructBsonSerialize<TValue> : StructSerializerBase<TValue> where TValue : struct
{
    private readonly List<PropertyInfo> propertyInfo = new List<PropertyInfo>();

    public override void Serialize(BsonSerializationContext context, BsonSerializationArgs args, TValue value)
    {
        Type nominalType = args.NominalType;
        var fields = nominalType.GetFields(BindingFlags.Instance | BindingFlags.Public);
        var propsAll = nominalType.GetProperties(BindingFlags.Instance | BindingFlags.Public);

        propertyInfo.Clear();
        foreach (var prop in propsAll)
        {
            if (prop.CanWrite)
            {
                propertyInfo.Add(prop);
            }
        }

        var bsonWriter = context.Writer;

        bsonWriter.WriteStartDocument();

        foreach (var field in fields)
        {
            bsonWriter.WriteName(field.Name);
            BsonSerializer.Serialize(bsonWriter, field.FieldType, field.GetValue(value));
        }
        foreach (var prop in propertyInfo)
        {
            if (prop.Name == "Item") continue;
            bsonWriter.WriteName(prop.Name);
            BsonSerializer.Serialize(bsonWriter, prop.PropertyType, prop.GetValue(value, null));
        }

        bsonWriter.WriteEndDocument();
    }

    public override TValue Deserialize(BsonDeserializationContext context, BsonDeserializationArgs args)
    {
        //boxing is required for SetValue to work
        var obj = (object)(new TValue());
        var actualType = args.NominalType;
        var bsonReader = context.Reader;

        bsonReader.ReadStartDocument();

        while (bsonReader.ReadBsonType() != BsonType.EndOfDocument)
        {
            var name = bsonReader.ReadName(Utf8NameDecoder.Instance);

            var field = actualType.GetField(name);
            if (field != null)
            {
                var value = BsonSerializer.Deserialize(bsonReader, field.FieldType);
                field.SetValue(obj, value);

            }

            var prop = actualType.GetProperty(name);
            if (prop != null)
            {
                var value = BsonSerializer.Deserialize(bsonReader, prop.PropertyType);
                prop.SetValue(obj, value, null);
            }
        }

        bsonReader.ReadEndDocument();

        return (TValue)obj;
    }
}